A SSHD is normally a 5400RPM drive mated with a SSD element as 'cache' to guess what it should read before you need it (think of a valet knowing to get your car hand you the keys and open the car door, all you need to do is get in and turn it on). The 'speed' of a SSHD is a bit better then a 7200RPM drive, which Samsung (the maker of SSHD) stopped making entirely. A SSD is actual memory chips read with no mechanical element increasing the speed in FACTORS (think Squared, Cubed, etc.) but suffers from both EXTREMELY EXPENSIVE (in comparision) and MUCH SHORTER LIFE SPANS.
The normal configuration is to get a SSD, do a COMPLETELY CLEAN OS INSTALL, then add the HDD (your 1TB) as a secondary storage. Install all applications to the SSD, but set any 'save files', my docs, music, etc. or REALLY BIG STUFF (think Battlefield 3) on the HDD. Further you need to manaually map all temp / log etc. disk activity to the HDD. There is quite a few 'step by steps' if you search for 'SSD Windows configuration' in google.
Plainly put this is for advanced users and geeks. If you dont' absolutely need to do this don't and just wait to upgrade to a system WITH it already installed (quite a few are already doing that). It is a much better investment that way.